The present invention relates to automatic pilot flame relighting devices and, more particularly to a novel electronic system for relighting a gas pilot flame which operates from a direct current power source.
In recreational vehicles having pilot lights incorporated in gas burner control systems for refrigerators, water heaters, heating system, and the like, the pilot light flame is sometimes extinguished due to air currents produced by passing vehicles, or by other causes. Although appropriate safety valves are normally provided to shut off the gas supply when the flame is extinguished, it is often inconvenient to relight the pilot burner and the associated equipment may be out of use for some time before the condition is discovered and corrected. This may result in expense due to spoilage of food in refrigerators, inconvenience due to lost travel time and unsafe conditions due to stopping vehicles in busy traffic. Indicator devices have been provided to signal the fact that the flame is out, but it is still necessary to relight the flame.
Automatic pilot flame relighting systems for household use are not suitable for employment in recreational vehicle applications since there is normally no convenient source of alternating current. Prior DC relighting systems have been provided which produce an essentially continuous spark, whether the pilot flame is burning, or not. These systems have the disadvantage of causing electrical interference with other equipment, such as television sets, etc. Other systems, such as some used for main burner ignition, are unsuitable due to their inability to operate reliably with widely varying input voltages. Variations encountered in typical battery converter installations may be as high as 400%. Furthermore, prior systems are generally unsuited to operate from a low voltage DC source, such as a typical vehicle storage battery.
It is a principal object of the present invention to provide a pilot flame relighting system which operates from a low voltage DC source and produces a relighting spark automatically in response to the pilot flame being extinguished.
Another object is to provide a DC pilot flame relighting device which operates with minimal power consumption.
A further object is to provide an automatic pilot light relighting circuit for DC operation which does not produce continuous electrical interference with other electrical appliances in the vicinity.
Still another object is to provide an automatic pilot flame relighting circuit capable of operating with an input voltage which may be subject to wide variations.
Other objects will in part be obvious and will in part appear hereinafter.